The product of the glnF gene, which is well-separated from the structural gene (glnA) for glutamine synthetase on the chromosme, is required for synthesis of glutamine synthetase in Salmonella. We are establishing conditions for studying the synthesis of glutamine synthetase in a cell-free protein synthesizing system from Salmonella using DNA from lambda flnA phages as template. We will prepare S30 fractions from glnF ion and glnF anion strains in order to purify the product of the glnF gene and determine the basis of the requirement for this positive regulatory factor. We have isolated strains that lack 3 of the 4 activities required for covalent modification of glutamine synthetase and have demonstrated that loss of these activities does not significantly affect derepression of the synthesis of glutamine synthetase in response to nitrogen limitation. We will attempt to isolate strains lacking the fourth activity (that of the (PII protein), and to map the genes for all proteins on the Salmonella chromosome. We have recently demonstrated that there is nitrogen control of the synthesis of proteins other than glutamine synthetase in Salmonella, namely of several periplasmic binding proteins that are components of amino acid transport systems. We will attempt to determine whether glutamine synthetase itself controls synthesis of these proteins or whether their synthesis is controlled by another regulatory factor, perhaps in conjunction with glutamine synthetase.